The present invention relates to an improvement of a bellows which permits twisting movement while the interior remains hermetically sealed.
Bellows are, in general, constructed by stacking a multiplicity of conical elements made of a thin plate material in a manner such that the cross section through the center axis is in the form of waves. Therefore, although folding action is provided to a considerable degree i.e., the expansion and contraction in the axial direction, the bellows are very weak with respect to twisting or torsional force.
However, bellows used for mechanical seals and bellows used to cope with the thermal expansion of high-temperature conduits are often subject to a torsional or twisting force. Therefore, there is an increasing demand to provide bellows suited for such applications and that do not rupture even under the conditions of torsional or twisting force.